I've got a cool alternative to the trackball that doesn't need any desk space, it works on the surface of my laptop. Now I can pile the paperwork right up to the edge! See www.futuremouse.com
I don't have a workbench anymore, but still have a messy desk, I'm afraid.

This is the problem with messy desks. If you work with a lot of hardware and prototyping, you have a lot stuff needed to do your work. Some of my larger prototype projects looked like I had dumped pots of spaghetti on several desks. Then add on to that test equipment, meters, parts, tools, and computers then you have what seems a cacophony of chaos. Surfing this undulating wave of disparate hardware is likely an engineer who is probably the only one in the company that fully understands that it is not chaos in their workspace but progress. Then enters the manager who job is to make everything follow “the plan”, reduce costs, systemize, “motivate” the workforce, and meet deadlines. In other words minimize chaos and promote order. When a manager sees what the engineer is doing, the manager skin crawls and seeks to help the engineer improve his productivity by introducing his version of order. To engineers, this is called stress. Managers look at engineers as hoarders and want them to get rid of the “junk” from previous projects. Then the same manager complains that following projects are continually delayed because the engineer keeps ordering and waiting for parts. The manager wants the engineer to clean up their work area to look pretty for customers who tour the area. Then the same manager complains that the engineer is wasting too much time searching for stored equipment and setting up projects. Then the manager makes everybody’s work space the same size then wonders why the hardware engineer has a rat’s nest of several projects on a single desk unlike the cooperative software engineers who can manage several programs on their computers just like the managers. When I had several desks and a larger room, my productivity increased. There are several other ways managers try to help engineers and then wonder why the engineer has a failure to thrive.

Yeah, trackballs are great, for that reason and also the reduced grope-around factor. But be sure to get a nice quiet one - last time I used a trackball at work, given my financial priorities and Scottish ancestry, it was a cheap one that made noise. Everyone else said it sounded like I was playing video games.

I would love to have the top manager at my last employer be made to look at these desks and then be shown how productive and creative the engineers were. He was one of those types who had outlines on the desk for where the phone and pad should be, and he valued neat far above organized. The same mind believed that all engineering talent was equal. Need I say more?